21477506 has 4 divisors (see below), whose sum is σ = 32216262. Its totient is φ = 10738752.

The previous prime is 21477503. The next prime is 21477509. The reversal of 21477506 is 60577412.

It is a semiprime because it is the product of two primes.

It is an interprime number because it is at equal distance from previous prime (21477503) and next prime (21477509).

It can be written as a sum of positive squares in only one way, i.e., 19492225 + 1985281 = 4415^2 + 1409^2 .

It is a super-2 number, since 2×21477506² = 922566527960072, which contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (21477503) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 5369375 + ... + 5369378.

Almost surely, 2^21477506 is an apocalyptic number.

21477506 is a deficient number, since it is larger than the sum of its proper divisors (10738756).

21477506 is a wasteful number, since it uses less digits than its factorization.

21477506 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 10738755.

The product of its (nonzero) digits is 11760, while the sum is 32.

The square root of 21477506 is about 4634.3830225824. The cubic root of 21477506 is about 277.9678809743.

The spelling of 21477506 in words is "twenty-one million, four hundred seventy-seven thousand, five hundred six".